Thermoplastic elastomer resin composition and connector

ABSTRACT

An object of the present invention is to provide a thermoplastic elastomer resin composition and a connector, which can be processed by mold forming and are excellent in the recycling property. The present invention provides a thermoplastic elastomer resin composition including 100 parts by weight of a base resin containing from 60 to 80 wt % of an acid-modified styrene-based elastomer and from 40 to 20 wt % of a syndiotactic polystyrene, and from 0 to 20 parts by weight of a hydrogenated dicyclopentadiene; and a connector using the composition.

This application is the International Stage of PCT Application No.PCT/JP2010/063507 filed Aug. 8, 2010, which claims priority of JapanPatent Application No. 2009-185657 filed Aug. 10, 2009.

TECHNICAL FIELD

The present invention relates to a thermoplastic elastomer resincomposition and a connector using the thermoplastic elastomer resincomposition.

BACKGROUND ART

In the industrial field such as automobile and home electric appliance,a seal material for sealing various members is generally used for thewaterproofing purpose. Such a seal material is composed, for example, ofan elastomer composition containing a thermosetting elastomer-made basematerial, a crosslinking agent and the like and having a crosslinkedstructure formed in the inside, or an elastomer composition described inPatent Document 1.

Also, in a wire harness routed in an automobile, for example, awaterproof connector 101 shown in FIG. 4 is used for preventing a liquidsuch as water from intruding into the connector to corrode a terminalfitting.

The waterproof connector 101 comprises a terminal fitting 102 formed bypressing an electrically conductive sheet metal or the like and aconnector housing 103 for housing the terminal fitting 102. The terminalfitting 102 comprises an electric wire connection part fixed to an end106 a of an electric wire 106 to establish connection of the core wireof the electric wire 106, and an electric contact part connected to theterminal fitting of the other-party connector. The connector housing 103is made of an insulating synthetic resin or the like and formed in a boxshape. The connector housing 103 comprises a terminal housing chamber103 a for housing the terminal fitting 102 in the inside. In theterminal housing chamber 103 a, a potting material 104 as a sealmaterial is injected.

The potting material 104 is composed of, for example, a liquid siliconerubber or an epoxy resin. The potting material 104 injected into theterminal housing chamber 103 a is cured by forming a crosslinkedstructure in the inside after a curing time under the predeterminedtemperature condition. Thanks to such curing of the potting material104, a liquid such as water is prevented from intruding into theterminal housing chamber 103 a, that is, the waterproof connector 101.

As for the waterproof connector not using the potting material, thefollowing waterproof connector is known. This waterproof connectorcomprises a terminal fitting, a connector housing, as described above,and a tubular holder fixed to the outside surface of an electric wireand at the same time, fixed to the connector housing. In the connectorhousing, a concave part for housing the holder is provided.

On the inside of the holder, a tubular packing put into close adherenceto both the inner surface of the holder and the outside surface of theelectric wire is fixed. Also, on the outside of the holder, a tubularpacking put into close adherence to both the outer surface of the holderand the inner surface of the concave part of the connector housing isfixed. Furthermore, in the portion between the electric wire connectionpart and the electric contact part of the terminal fitting, an O-ringput into close adherence to both the outer surface of the terminalfitting and the inner surface of the connector housing is fixed.

Thanks to the configuration above, the portion between the holder andthe electric wire, the portion between the holder and the connectorhousing, that is, between the electric wire and the connector housing,or the portion between the terminal fitting and the connector housing iskept watertight, and a liquid such as water is prevented from intrusioninto the waterproof connector.

RELATED ART DOCUMENT Patent Document

-   Patent Document 1: JP-A-6-340705

SUMMARY OF THE INVENTION Problems that the Invention is to Solve

However, the above-described waterproof connector 101 requires work forinjecting the potting material 104 and therefore, suffers from a problemthat the number of productions steps is large and the workability isbad. Also, a curing time for curing the potting material 104 isnecessary, and this is disadvantageous in that the product stays in theproduction step during the curing time and the productivity decreases.Furthermore, the potting material 104 is injected into a wide space inthe terminal housing chamber 103 a, and there is a problem that theamount used is increased to raise the material cost.

In recent years, considering the environmental problem, at theautomobile dismantling such as car disposal, the parts are required tobe separated/recovered based on the material contained therein andsubsequently recycled, but the seal material or potting material 104described in Patent Document 1 contains a crosslinked structure in theinside and this gives rise to a problem that thermal deformationscarcely occurs even when reheated and the recycling property is bad.

Also, the waterproof connector not using the potting material 104requires parts such as holder and packing and suffers from a problemthat the number of parts or production steps is increased and the costrises. In addition, there is a problem that the connecter grows in sizedue to the holder.

An object of the present invention is to solve these problems. That is,an object of the present invention is to provide a thermoplasticelastomer resin composition and a connector, which can be processed bymold forming and are excellent in the recycling property.

Means for Solving the Problems

In order to solve the above-described problems and attain the object,the following thermoplastic elastomer resin composition and connectorare provided.

[1] A thermoplastic elastomer resin composition comprising 100 parts byweight of a base resin containing from 60 to 80 wt % of an acid-modifiedstyrene-based elastomer and from 40 to 20 wt % of a syndiotacticpolystyrene, and from 0 to 20 parts by weight of a hydrogenateddicyclopentadiene.

[2] The thermoplastic elastomer resin composition as described in [1]above, which further contains from 0.5 to 1.5 parts by weight of aphenolic antioxidant and from 1.0 to 3.0 parts by weight of aphosphorous acid ester-based antioxidant, per 100 parts by weight of thebase resin.

[3] A connector, wherein at least a part of the members are formed ofthe thermoplastic elastomer resin composition described in [1] or [2]above.

[4] A connector comprising a terminal fitting having an electric contactpart put into connection to a terminal fitting of the other-partyconnector and an electric wire connection part continuing from theelectric contact part and being connected to the end of an electricwire, at least a part of the electric contact part being disposed in afirst mold resin, the portion between the electric contact part and thefirst mold resin being sealed with an annular seal member, the electricwire connection part being embedded in the first mold resin, and theelectric wire and the electric wire lead-out port of the first moldresin being sealed with a second mold resin, wherein the second moldresin is formed of the thermoplastic elastomer resin compositiondescribed in [1] or [2] above.

[5] The connector as described in [4] above, wherein the first moldresin is formed of a resin composition containing at least one resinselected from the group consisting of a polystyrene-based resin, apolyamide-based resin, a polyester-based resin, a modified polyphenyleneether and a polyphenylene sulfide.

Advantage of the Invention

According to the invention described in [1] above, the thermoplasticelastomer resin composition comprises 100 parts by weight of a baseresin containing from 60 to 80 wt % of an acid-modified styrene-basedelastomer and from 40 to 20 wt % of a syndiotactic polystyrene, and from0 to 20 parts by weight of a hydrogenated dicyclopentadiene, so that thecomposition can be excellent in the heat resistance and adhesiveness(thermal adhesiveness) to other parts, ensuring excellent sealingproperty, and at the same time, can be processed by mold forming andtherefore, enhanced in the workability and productivity. Also, since acrosslinked structure is not contained in the inside, the recyclingproperty can be enhanced. Furthermore, the thermoplastic elastomer resincomposition contains, as an arbitrary component, from 0 to 20 parts byweight of a hydrogenated dicyclopentadiene, so that the strength can beexcellent and the tensile strength and percentage elongation at breakcan be more enhanced.

According to the invention described in [2] above, the thermoplasticelastomer resin composition further contains from 0.5 to 1.5 parts byweight of a phenolic antioxidant and from 1.0 to 3.0 parts by weight ofa phosphorous acid ester-based antioxidant, per 100 parts by weight ofthe base resin, so that oxidative degradation can be prevented and thecomposition can be endowed with more excellent heat resistance.

According to the invention described in [3] above, at least a part ofthe members are formed of the thermoplastic elastomer resin compositiondescribed in [1] or [2] above, so that the connector can be a connectorexcellent in the sealing property and recycling property.

According to the invention described in [4] above, the second mold resinis formed of the above-described thermoplastic elastomer resincomposition, so that the electric wire and the electric wire lead-outport can be sealed by mold forming, dispensing with pottingmaterial-injecting work or curing time, and the workability andproductivity can be enhanced. Also, the amount of the composition usedis small compared with the potting material and therefore, the materialcost can be reduced. Furthermore, since the second mold resin does notcontain a crosslinked structure, the recycling property can be enhanced.

According to the invention described in [5] above, the first mold resinis formed of a resin composition containing at least one resin selectedfrom the group consisting of a polystyrene-based resin, apolyamide-based resin, a polyester-based resin, a modified polyphenyleneether and a polyphenylene sulfide, so that the terminal fitting can beembedded in a highly insulating resin composition. Also, a general resincomposition can be used for the first mold resin and therefore, thematerial cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 A perspective view showing the connector according to oneembodiment of the present invention.

FIG. 2 A cross-sectional view along the line II-II in FIG. 1.

FIG. 3 A cross-sectional view showing a modification example of theconnector shown in FIG. 2.

FIG. 4 A cross-sectional view showing a conventional connector.

MODE FOR CARRYING OUT THE INVENTION

The thermoplastic elastomer resin composition according to oneembodiment of the present invention is described below. Thethermoplastic elastomer resin composition according to one embodiment ofthe present invention comprises 100 parts by weight of a base resinconsisting of from 60 to 80 wt % of an acid-modified styrene-basedelastomer and from 40 to 20 wt % of a syndiotactic polystyrene, from 0.5to 1.5 parts by weight of a phenolic antioxidant, from 1.0 to 3.0 partsby weight of a phosphorous acid ester-based antioxidant, and from 0 to20 parts by weight of a hydrogenated dicyclopentadiene.

Examples of the acid-modified styrene-based elastomer include anacid-modified styrene-ethylene-butylene-styrene block copolymer(hereinafter, referred to as acid-modified SEBS) and an acid-modifiedstyrene-butylene-styrene block copolymer (hereinafter, referred to asacid-modified SBS). These may be used individually or in combination.Also, the acid-modified styrene-based elastomer is not limited only tothese copolymers and as long as the object of the present invention isnot violated, an acid-modified styrene-based elastomer other than thosedescribed above may be also used.

The acid-modified SEBS is obtained by modifying the ethylene-butyleneblock in a styrene-ethylene-butylene-styrene block copolymer with anacid such as maleic anhydride. Also the acid-modified SBS is obtained bymodifying the butylene block in a styrene-butylene-styrene blockcopolymer with an acid such as maleic anhydride. The acid-modifiedstyrene-based elastomer has high adhesiveness to a metal or a resincompared with an unmodified styrene-based elastomer. As for thecommercial product of such an acid-modified styrene-based elastomer, theacid-modified SEBS includes, for example, Tuftec M1913, trade name(produced by Asahi Kasei Chemicals Corp.).

The syndiotactic polystyrene (hereinafter, referred to as SPS) is apolystyrene where benzene rings are regularly and alternately disposedwith respect to the main chain. The SPS is high in the heat resistanceand chemical resistance compared with an atactic polystyrene (apolystyrene where benzene rings are randomly disposed with respect tothe main chain). The commercial product of such SPS includes, forexample, XAREC S104, trade name (produced by Idemitsu Kosan Co., Ltd.).

The base resin contains from 60 to 80 wt % of an acid-modifiedstyrene-based elastomer and from 40 to 20 wt % of SPS and is preferablycomposed of an acid-modified styrene-based elastomer and SPS. If thecontent of the acid-modified styrene-based elastomer is less than 60 wt% (that is, the content of SPS exceeds 40 wt %), sufficient sealingproperty or adhesiveness cannot be obtained, whereas if the content ofthe acid-modified styrene-based elastomer exceeds 80 wt % (that is, thecontent of SPS is less than 20 wt %), adequate heat resistance is notobtained. The SPS exhibits good molecular dispersibility for theacid-modified styrene-based elastomer and since its glass transitiontemperature is high compared with polyethylene and polypropylene, theheat resistance of the base resin can be effectively enhanced.

Examples of the phenolic antioxidant includetris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,2,6-di-tert-butyl-4-methylphenol, tetrakis[methylene-3(3′,5′-di-tert-butyl-4-hydroxyphenyl)propionate]methane,octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane,1,3,5-tris-2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethylisocyanate,1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,pentaerythritoltetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],triethyleneglycol-N-bis-3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate,1,6-hexanediolbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],2,2-thiobis-diethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate],2,2′-methylene-bis-(4-methyl-6-tert-butylphenol),2,2′-methylene-bis-(4-ethyl-6-tert-butylphenol),2,2′-methylene-bis-(4,6-di-tert-butylphenol),2,2′-ethylidene-bis-(4,6-di-tert-butylphenol) (CHEMINOX 1129),2,2′-butylidene-bis-(4-methyl-6-tert-butylphenol),4,4′-butylidenebis(3-methyl-6-tert-butylphenol),2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate,2,4-di-tert-amyl-6-[1-(3,5-di-tert-amyl-2-hydroxyphenyl)ethyl]phenylacrylate, and tocopherols. Specific examples of the tocopherols includeα-tocopherol (5,7,8-trimethyltocol), (β-tocopherol (5,8-dimethyltocol),γ-tocopherol (7,8-dimethyltocol), and δ-tocopherol (8-methyltocol). Oneof these may be used alone, or two or more thereof may be used incombination. Also, the phenolic antioxidant is not limited only to thesecompounds and as long as the object of the present invention is notviolated, a phenolic antioxidant other than those described above may beused.

The phenolic antioxidant is preferably added to account for from 0.5 to1.5 parts by weight per 100 parts by weight of the base resin. If thecontent of the phenolic antioxidant is less than 0.5 parts by weight,the resin composition may be degraded by oxidation ascribableparticularly to a radical and the heat resistance may be reduced. Also,even if the content of the phenolic antioxidant exceeds 1.5 parts byweight, the heat resistance is scarcely enhanced in association with theincrease in the amount added but the sealing property or adhesivenessmay be reduced or bleed may be generated on the resin compositionsurface.

Examples of the phosphorous acid ester-based antioxidant includetris(2,4-di-tert-butylphenyl)phosphite,bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphorousacid, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4′-diylbisphosphonite,bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite,distearylpentaerythritol diphosphite, triphenyl phosphite, tetraphenyldipropylene glycol diphosphite,tetraphenyltetra(tridecyl)pentaerythritol tetraphosphite, tetra(C12-C15alkyl)-4,4′-isopropylidene phenylphosphite, bis(tridecyl)pentaerythritoldiphosphite, bis(nonylphenyl)pentaerythritol diphosphite,4,4′-butylidenebis(3-methyl-6-tert-butylphenyl-ditridecylphosphite),tristearyl phosphite, hydrogenated bisphenol A.entaerythritol phosphitepolymer, hydrogenated bisphenol A.phosphite polymer, trisnonylphenylphosphite, tricresyl phosphite, triethyl phosphite,tris(2-ethylhexyl)phosphite, tridecyl phosphite, trilauryl phosphite,tris(tridecyl)phosphite, trioleyl phosphite,diphenylmono(2-ethylhexyl)phosphite, diphenylmonodecyl phosphite,diphenylmono(tridecyl)phosphite, trilauryl trithiophosphite, diethylhydrogenphosphite, dilauryl hydrogenphosphite, dioleyl hydrogenphoshite,and diphenyl hydrogenphosphite. One of these may be used alone, or twoor more thereof may be used in combination. Also, the phosphorous acidester-based antioxidant is not limited only to these compounds and aslong as the object of the present invention is not violated, aphosphorous acid ester-based antioxidant other than those describedabove may be used.

The phosphorous acid ester-based antioxidant is preferably added toaccount for 1.0 to 3.0 parts by weight per 100 parts by weight of thebase resin. If the content of the phosphorous acid ester-basedantioxidant is less than 1.0 parts by weight, the resin composition maybe degraded by oxidation ascribable to a peroxide generated particularlyunder high temperature, for example, during shaping and the heatresistance may be reduced. Also, even if the content of the phosphorousacid ester-based antioxidant exceeds 3.0 parts by weight, the heatresistance is scarcely enhanced in association with the increase in theamount added but the sealing property or adhesiveness may be reduced orbleed may be generated on the resin composition surface.

The thermoplastic elastomer resin composition having the above-describedconfiguration may further contain, as an arbitrary component, from 0 to20 parts by weight of a hydrogenated dicyclopentadiene (hereinafter,referred to as hydrogenated DCPD) per 100 parts by weight of the baseresin. The hydrogenated DCPD is a dicyclopentadiene in which hydrogen isadded to the carbon double bond of the dicyclopentadiene, and thehydrogenation ratio is not particularly limited. The hydrogenated DCPDenhances the strength (hardness), tensile strength and percentageelongation at break of the resin composition. The commercial product ofsuch hydrogenated DCPC includes, for example, Oppera PR130J (produced byExxon Mobil Corp.).

The hydrogenated DCPD is added to account for 0 to 20 parts by weightper 100 parts by weight of the base resin. If the content of thehydrogenated DCPD exceeds 20 parts by weight, the heat resistance isreduced.

The thermoplastic elastomer resin composition of the present inventionis formulated in the above-described configuration. By containing anacid-modified styrene-based elastomer, the adhesiveness to a metal or aresin is enhanced; by containing SPS, the heat resistance is enhanced;and by containing a phenolic antioxidant or a phosphorous acidester-based antioxidant, oxidative degradation is prevented and the heatresistance is more enhanced. Furthermore, by containing hydrogenatedDCPD as an arbitrary component, the strength (hardness), tensilestrength and percentage elongation at break are improved.

Incidentally, the thermoplastic elastomer resin composition of thepresent invention has sufficient heat resistance even without containingthe phenolic antioxidant or phosphorous acid ester-based antioxidantabove. However, by containing such an antioxidant in an amount of theabove-described parts by weight, the heat resistance can be moreenhanced. Also, the thermoplastic elastomer resin composition maycontain various additives (for example, a stabilizer such as lightstabilizer, a flame retardant, an antistatic agent, a filler and acolorant) within the range not impairing the effects of the presentinvention.

The thermoplastic elastomer resin composition formulated in theabove-described configuration is melt-kneaded and obtained as aso-called polymer alloy. As for the melt-kneading method, various knowntechniques may be used. For example, the components are previouslypre-blended using a high-speed mixing apparatus or the like such asHenschel mixer and then melt-kneaded using a single-screw extruder, atwin-screw extruder or the like, and the melt is injected into a moldand formed into a desired shape, for example, a water-stopping part 4 ofthe later-described connector 1. The thus-formed thermoplastic elastomerresin composition does not contain a crosslinked structure in the insideand therefore, can be re-formed by heating it at not less than a giventemperature and easily recycled.

The connector using the thermoplastic elastomer resin composition of thepresent invention is described below by referring to FIGS. 1 and 2. Asshown in FIG. 1, the connector 1 comprises a terminal fitting 2, ahousing part 3, and a water-stopping part 4.

The terminal fitting 2 is formed, for example, by bending anelectrically conductive sheet metal or the like. The terminal fitting 2is composed, for example, of a copper alloy such as brass. Also, theterminal fitting 2, either in a sheet metal state before bending or in aterminal fitting 2 state after bending, may be plated with tin, silveror gold. That is, the outside surface of the terminal fitting 2 iscomposed of a copper alloy, tin, silver or gold. As shown in FIG. 2, theterminal fitting 2 is a so-called male-type terminal fitting, and thisterminal fitting integrally comprises an electric contact part 21 and anelectric wire connection part 22 and is formed in an L-shape.

The electric contact part 21 is formed in a belt-like shape. The baseend part 21 a on the electric wire connection part 22 side of theelectric contact part 21 is embedded in the housing part 3. The distalpart 21 b of the electric contact part 21 projects from the housing part3 and is electrically connected to the terminal fitting (not shown) ofthe other-party connector. The central part 21 c of the electric contactpart 21 is disposed in the housing part 3 in a state of leaving a gapbetween the central part and the inner surface of the housing part 3. Atthe end on the base end part 21 a side of the central part 21 c, anO-ring 52 as an annular seal member composed of an elastic material suchas rubber is fixed.

The electric wire connection part 22 is formed in a belt-like shape andembedded in the housing part 3. The electric wire connection part 22 isprovided to bend from the electric contact part 21 and be perpendicularto the electric contact part 21. In the example shown in the Figure, theangle between the electric wire connection part 22 and the electriccontact part 21 is nearly 90°.

On the electric wire connection part 22, a core wire 61 exposed to theend 6 a of the later-described electric wire 6 is placed. The electricwire connection part 22 and the core wire 61 are connected by ultrasonicwelding or heat welding. By way of ultrasonic welding or heat welding,the electric wire connection part 22 is electrically and mechanicallyconnected to an electric wire 6. As for the method to connect theelectric wire connection part 22 and the electric wire 6, the core wire61 may be caulked with a caulking piece by providing the caulking piecein the electric wire connection part 22.

The electric wire 6 is a so-called cable. As shown in FIG. 2, theelectric wire 6 comprises an electrically conductive core wire 61 and aninsulating coat part 62. The core wire 61 is composed of a single wire.The single wire constituting the core wire 61 is made of an electricallyconductive metal such as copper and aluminum. Incidentally, the corewire 61 may be formed by twisting a plurality of wires.

The coat part 62 is made of an insulating synthetic resin or the likeand, for example, composed of a synthetic resin such aspolyethylene-based resin, polypropylene-based resin and polyvinylchloride resin. That is, the outside surface of the coat part 62 iscomposed of a synthetic resin such as polyethylene-based resin,polypropylene-based resin and polyvinyl chloride resin. The coat part 62covers the core wire 61. The coat part 62 is peeled at the end 6 a ofthe electric wire 6 to expose the core wire 61.

The housing part 3 is composed of a first mold resin, and the base endpart 21 a of the electric contact part 21 as well as the electric wireconnection part 22 of the terminal fitting 2 and the end 6 a of theelectric wire 6, where the water-stopping part 4 is formed, are embeddedtherein. The first mold resin is a resin composition different from thethermoplastic elastomer resin composition of the present invention. Thefirst mold resin includes a known resin composition used as a materialconstituting the connector housing of a general connector. Above all,the mold resin is preferably formed of a resin composition containing atleast one resin selected from the group consisting of apolystyrene-based resin, a polyamide-based resin, a polyester-basedresin, a modified polyphenylene ether and a polyphenylene sulfide, morepreferably formed of a resin composition containing a syndiotacticpolystyrene resin.

The housing part 3 is shaped integrally with the terminal fitting 2 andthe electric wire 6 having formed thereon the water-stopping part 4, bymold forming. As shown in FIG. 1, the housing part 3 integrallycomprises a cylindrical part 31 and an angular tube part 32 continuingfrom the cylindrical part 31 and is formed in an L-shape as a whole. Onthe outside surface of the cylindrical part 31, a tubular packing 51composed of an elastic material such as rubber is fixed.

The cylindrical part 31 is formed in a cylindrical shape. Inside of thecylindrical part 31, the base end part 21 a of the electric contact part21 of the terminal fitting 2 is embedded in a state of the inner surfaceof the cylindrical part being tightly contacted with the outside surfaceof the base end part 21 a (not necessarily watertight). Also thecylindrical part 31 houses the central part 21 c of the electric contactpart 21 in the inside in a state of leaving a gap between the innersurface and the outside surface of the central part 21 c. In this gap,the above-described O-ring 52 fixed in the central part 21 c is located.The O-ring 52 closely adheres (watertight) to the inner surface of thecylindrical part 31 and the outside surface of the central part 21 c.The portion between the electric contact part 21 and the housing part 3is kept watertight (sealed) by the O-ring 52 to prevent a liquid such aswater sliding down the distal part 21 b of the electric contact part 21from intruding into the housing part 3.

The angular tube part 32 is formed in an angular tube shape. The angulartube part 32 is provided to continue from the end of the cylindricalpart 31 and be orthogonal to the cylindrical part 31. Inside of theangular tube part 32, the electrical wire connection part 22 of theterminal fitting 2 and the end 6 a of the electric wire 6, where thewater-stopping part 4 is formed, are embedded. The inner surface of theangular tube part 32 is tightly contacted with the outside surface ofthe electrical wire connection part 22, the core wire 61 of the electricwire 6, and the outside surface of the coat part 62. Also, the innersurface of the angular tube part 32 closely adheres to the outsidesurface of the water-stopping part. The end of the angular tube part 32,which is remote from the cylindrical part 31, serves as the electricwire lead-out port 33.

The electric wire lead-out port 33 is formed in an angular tube shapeand guides the electric wire 6 having formed thereon a water-stoppingpart 4 to the outside of the housing part 3. The inner surface of theelectric wire lead-out port 33 closely adheres to the outside surface ofthe water-stopping part 4, and the portion between the inner surface andthe water-stopping part 4 is kept watertight.

The water-stopping part 4 is composed of a second mold resin and sealsthe portion between the electric wire lead-out port 33 and the end 6 aof the electric wire 6. The second mold resin is formed of thethermoplastic elastomer resin composition of the present invention. Thethermoplastic elastomer resin composition of the present invention ispreferred because of its excellent adhesiveness to the first mold resinor the synthetic resin constituting the coat part 62 of the electricwire 6, such as polyethylene-based resin, polypropylene-based resin andpolyvinyl chloride resin. Also, the thermoplastic elastomer resincomposition of the present invention is excellent in the heat resistanceand therefore, for example, a connector 1 is advantageously kept frombreakage even when disposed under a severe temperature condition such asin an engine room of automobile.

As shown in FIG. 1, the water-stopping part 4 is formed in a cylindricalshape. The water-stopping part 4 is shaped integrally with the electricwire 6 and the housing part 3 by mold forming. As shown in FIG. 2, thewater-stopping part 4 is continuously provided over a region from theoutside surface of the coat part 62 of the electric wire 6 in theportion embedded in the housing part 3 to the outside surface in theportion disposed outside of the housing part 3 and closely adheres tothe outside surface of the coat part 62. Also, the water-stopping part 4closely adheres to the inner surface of the electric wire lead-out port33. Such a water-stopping part 4 seals the portion between the electricwire 6 and the electric wire lead-out port 33 to keep the portionwatertight and prevent a liquid such as water sliding down the electricwire 6 from intruding into the housing part 3 and attaching to theterminal fitting 2.

On the outside surface of the water-stopping part 4 located outside ofthe housing part 3, as shown in FIG. 1, a groove 4 a is provided. Thegroove 4 a is provided along the circumferential direction of thewater-stopping part 4 and a plurality of grooves are provided to alignalong the circumferential direction. Furthermore, a plurality of grooves4 a are provided with a spacing from each other along the central axisof the water-stopping part 4. Thanks to these grooves 4 a, bending ofthe water-stopping part 4 and in turn, bending of the electric wire 6inside the water-stopping part 4 are facilitated, and the degree offreedom at the electric wire 6 routing is increased.

At the time of producing a connector 1 having the above-describedconfiguration, first, the electric wire connection part 22 of theterminal fitting 2 is fixed to the electric wire 6 before forming thewater-stopping part 4, by ultrasonic welding or heat welding. Next, thewater-stopping part 4 is mold-formed in the coat part 62 at the end 6 aof the electric wire 6. That is, the end 6 a of the electric wire 6 isfixed at a predetermined position within a first mold (not shown) usedfor mold-forming the water-sopping part 4, and shaping of themelt-kneaded second mold resin, that is, the thermoplastic elastomerresin composition of the present invention, is performed in the firstmold. After the shaping, the integrally formed electric wire 6 andwater-stopping part 4 are taken out of the first mold.

Subsequently, the housing part 3 is mold-formed. That is, the end 6 a ofthe electric wire 6 having formed thereon the water-stopping part 4, andthe base end part 21 a of the electric contact part 21 as well as theelectric wire connection part 22 of the terminal fitting 2 fixed to theelectric wire 6 are fixed at predetermined positions within a secondmold (not shown) used for mold-forming the housing part 3, and shapingof the melt-kneaded first mold resin is performed in the second mold.After the shaping, the integrally formed terminal fitting 2, housingpart 3 and electric wire 6 are taken out of the second mold. Finally,the O-ring 52 is fixed to closely adhere to both the central part 21 cof the electric contact part 21 of the terminal fitting 2 and the innersurface of the cylindrical part 31 of the housing part 3, and theportion between the terminal fitting 2 and the housing part 3 is therebymade watertight. In this way, the connector 1 shown in FIGS. 1 and 2 isproduced.

According to this embodiment, the thermoplastic elastomer resincomposition comprises 100 parts by weight of a base resin containingfrom 60 to 80 wt % of an acid-modified styrene-based elastomer and from40 to 20 wt % of SPS, and from 0 to 20 parts by weight of hydrogenatedDCPD, so that the composition can be excellent in the heat resistanceand adhesiveness (thermal adhesiveness) to other parts, ensuringexcellent sealing property, and at the same time, can be processed bymold forming and therefore, enhanced in the workability andproductivity. Also, since a crosslinked structure is not contained inthe inside, the recycling property can be enhanced. Furthermore, thethermoplastic elastomer resin composition contains, as an arbitrarycomponent, from 0 to 20 parts by weight of hydrogenated DCPD, so thatthe strength can be excellent and the tensile strength and percentageelongation at break can be more enhanced.

Also, the thermoplastic elastomer resin composition further containsfrom 0.5 to 1.5 parts by weight of a phenolic antioxidant and from 1.0to 3.0 parts by weight of a phosphorous acid ester-based antioxidant,per 100 parts by weight of the base resin, so that oxidative degradationcan be prevented and the composition can be endowed with more excellentheat resistance.

In addition, the second mold resin is formed of the thermoplasticelastomer resin composition of the present invention, so that theelectric wire 6 and the electric wire lead-out port 33 can be sealed bymold forming, dispensing with potting material-injecting work or curingtime, and the workability and productivity can be enhanced. Also, theamount of the composition used is small compared with the pottingmaterial and therefore, the material cost can be reduced. Furthermore,since the second mold resin does not contain a crosslinked structure,the recycling property can be enhanced.

The first mold resin is formed of a resin composition containing atleast one resin selected from the group consisting of apolystyrene-based resin, a polyamide-based resin, a polyester-basedresin, a modified polyphenylene ether and a polyphenylene sulfide, sothat the terminal fitting 2 can be embedded in a highly insulating resincomposition. Also, a general resin composition can be used for the firstmold resin and therefore, the material cost can be reduced.

In the embodiment above, a case of using the thermoplastic elastomerresin composition of the present invention for a connector 1 isdescribed, but the thermoplastic elastomer resin composition of thepresent invention may be of course used for sealing of other articles.

Also, in the connector 1, the housing part 3 is mold-formed aftermold-forming the water-stopping part 4, but the connector 1 may be aconnector 1A shown in FIG. 3 and the water-stopping part 4A may bemold-formed after mold-forming the housing part 3. Incidentally, for thesame constituent portions as in the embodiment above, like numerals areused and their description are omitted.

The electric wire lead-out port 33A of the housing part 3 is formed in acylindrical shape with the outer diameter being smaller than that of theangular tube part 32. The water-stopping part 4A is continuouslyprovided over a region from the outside surface of the electric wirelead-out port 33A to the outside surface of the coat part 62 at the end6 a of the electric wire 6 guided through the electric wire lead-outport 33A and is formed to cover the electric wire lead-out port 33A andthe end 6 a of the electric wire 6. The water-stopping part 4A closelyadheres to both the outside surface of the electric wire lead-out port33A and the outside surface of the coat part 62 at the end 6 a of theelectric wire 6. This water-stopping part 4A seals the portion betweenthe electric wire 6 and the electric wire lead-out port 33A to keep theportion watertight and prevent a liquid such as water sliding down theelectric wire 6 from intruding into the housing part 3 and attaching tothe terminal fitting 2.

The above-described embodiments are merely a representative embodimentof the present invention, and the present invention is not limited tothese embodiments. That is, the present invention can be performed bymaking various modifications therein within the range not deviating fromthe gist of the present invention.

EXAMPLES Example 1

A base resin was prepared by blending 70 wt % of acid-modified SEBS(Tuftec M1913, produced by Asahi Kasei Chemicals Corp.) as theacid-modified styrene-based elastomer and 30 wt % of SPS (XAREC 5104,produced by Idemitsu Kosan Co., Ltd.), and 1.5 parts by weight of aphenolic antioxidant (IRGANOX 3114, produced by Ciba SpecialtyChemicals) and 2.0 parts by weight of a phosphorous acid ester-basedantioxidant (ADK STAB 2112, produced by ADECA Corp.) were blended per100 parts by weight of the base resin. These were mixed in a Henschelmixer, and the mixture was melt-kneaded using a same-directiontwin-screw extruder (φ40 mm, L/D=45) and extrusion-formed at anextrusion speed of 600 mm/min to form a columnar pellet (φ3.0 mm).

As for the heater of the twin-screw extruder above, 6 heaters in total,that is, 5 heaters provided in a line along the longitudinal directionof the cylinder between the hopper port and the head for heating theinside of the cylinder and 1 heater for heating the head, are provided.These heaters were set to a temperature of 230° C., 255° C., 270° C.,240° C., 240° C. and 250° C., respectively, from the hopper port towardthe head. At this time, the actual temperature of the meltedthermoplastic elastomer resin composition was about 280° C.

Example 2

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 3

A base resin was prepared by blending 80 wt % of the acid-modified SEBSabove and 20 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 4

A base resin was prepared by blending 70 wt % of the acid-modified SEBSabove and 30 wt % of the SPS above, 10 parts by weight of hydrogenatedDCPD (Oppera PR130J, produced by Exxon Mobil Corp.), 1.5 parts by weightof the phenolic antioxidant above and 2.0 parts by weight of thephosphorous acid ester-based antioxidant above were blended per 100parts by weight of the base resin, and thereafter, a columnar pellet wasformed in the same manner as in Example 1.

Example 5

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 10 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

Example 6

A base resin was prepared by blending 80 wt % of the acid-modified SEBSabove and 20 wt % of the SPS above, 10 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

Example 7

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 0.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 8

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 1.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 9

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 3.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 10

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 5 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

Example 11

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 20 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

Example 12

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 0.2 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 13

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 0.5 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 14

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 2.0 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Example 15

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 4.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Comparative Example 1

A base resin was prepared by blending 90 wt % of the acid-modified SEBSabove and 10 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Comparative Example 2

A base resin was prepared by blending 50 wt % of the acid-modified SEBSabove and 50 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Comparative Example 3

A base resin was prepared by blending 30 wt % of the acid-modified SEBSabove and 70 wt % of the SPS above, 1.5 parts by weight of the phenolicantioxidant above and 2.0 parts by weight of the phosphorous acidester-based antioxidant above were blended per 100 parts by weight ofthe base resin, and thereafter, a columnar pellet was formed in the samemanner as in Example 1.

Comparative Example 4

A base resin was prepared by blending 90 wt % of the acid-modified SEBSabove and 10 wt % of the SPS above, 10 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

Comparative Example 5

A base resin was prepared by blending 75 wt % of the acid-modified SEBSabove and 25 wt % of the SPS above, 30 parts by weight of thehydrogenated DCPD above, 1.5 parts by weight of the phenolic antioxidantabove and 2.0 parts by weight of the phosphorous acid ester-basedantioxidant above were blended per 100 parts by weight of the baseresin, and thereafter, a columnar pellet was formed in the same manneras in Example 1.

The formed articles obtained in Examples 1 to 15 and ComparativeExamples 1 to 5 were subjected to the following evaluations (evaluationof sealing property, evaluation of adhesiveness, evaluation of heatresistance), and the results are shown together in Tables 1 to 3. Also,the formed articles obtained in Examples 1 and 4 and ComparativeExamples 1 and 4 were measured for the following physical properties(specific gravity, hardness, tensile strength, percentage elongation atbreak), and the results are shown together in Table 4.

(Evaluation of Sealing Property)

A connector 1 shown in FIG. 1 was produced using the thermoplasticelastomer of the present invention formed into a pellet as above, theconnector 1 was set on an aluminum-made jig and immersed in water, atube was passed through the jig, a compressed air of 10.0 kPa was fedbetween the water-stopping part 4 and the electric wire 6 from the tubefor 30 seconds, and the leakage of the compressed air from between thewater-stopping part 4 and the housing part 3 was observed. When leakageof the compressed air was not observed, the pressure of the compressedair was raised in steps of 10.0 kPa. The pressure of the compressed airwhen leakage was observed was taken as the seal pressure, and thesealing property was judged as passed (A) when the seal pressure was 200kPa or more, judged as practically no problem (B) when from 100 kPa toless than 200 kPa, and judged as failed (C) when less than 100 kPa.

(Evaluation of Adhesiveness)

The evaluation was performed in accordance with JIS K 6854-2 (2008).Together with a sheet-like formed article (polystyrene-based resin,length: 150.0 mm, width: 25.0 mm, thickness: 3.0 mm) as the adherend,the thermoplastic elastomer of the present invention formed into apellet as above was integrally formed into a sheet (length: 100.0 mm,width 20.0 mm, thickness: 3.0 mm) by using an injection molding machineto prepare a test piece, and a 180° peel test was performed by anautograph (manufactured by Shimadzu Corp.). The adhesiveness was judgedas passed (A) when the peel adhesive strength was 1.0 N/mm or more,judged as practically no problem (B) when from 0.3 N/mm to less than 1.0N/mm, and judged as failed (C) when less than 0.3 N/mm.

(Evaluation of Heat Resistance)

The thermoplastic elastomer of the present invention formed into apellet as above was formed into a sheet by a twin roller, further formedinto a sheet by an electrically heated press and then cut (length: 100.0mm, width: 20.0 mm, thickness: 2.0 mm) to prepare a test piece, andafter heating and aging by leaving it at 140° C. for 120 hours, the heatresistance was judged as passed (A) when the outer appearance was lessdiscolored and cracking was not generated in the outside surface of theformed article by 180° bending, judged as passed (B) when thediscoloration of the outer appearance was moderate and the crackingabove was not generated, and judged as failed (C) when the outerappearance was greatly discolored and the cracking above was generated.

(Measurement of Specific Gravity)

The measurement was performed in accordance with JIS K7112 Method A(2008). The thermoplastic elastomer of the present invention formed intoa pellet as above was formed into a sheet by a twin roll, further formedinto a sheet by an electrically heated press and then cut (length: 30.0mm, width: 20.0 mm, thickness: 2.0 mm) to prepare a test piece.

(Measurement of Hardness)

The measurement was performed in accordance with JIS K6253 (2008). Thethermoplastic elastomer of the present invention formed into a pellet asabove was formed into a sheet by a twin roll, further formed into asheet by an electrically heated press and then cut (length: 50.0 mm,width: 20.0 mm, thickness: 6.0 mm) to prepare a test piece. A durometerhardness test was performed using a type A durometer. A pressure platewas contacted with the test piece, and the hardness was read immediatelyand after 10 seconds.

(Measurement of Tensile Strength)

The measurement was performed in accordance with JIS K6251 (2008). Thethermoplastic elastomer of the present invention formed into a pellet asabove was formed into a sheet by a twin roll, further formed into asheet by an electrically heated press, then cut (thickness: 2.0 mm) andpunched into a dumbbell No. 3 shape to prepare a test piece. The tensilespeed was set to 500 mm/min.

(Measurement of Percentage Elongation at Break)

The measurement was performed in accordance with JIS K6251 (2008). Thepellet-like formed article above of the thermoplastic elastomer of thepresent invention was formed into a sheet by a twin roll, further formedinto a sheet by an electrically heated press, then cut (thickness: 2.0mm) and punched into a dumbbell No. 3 shape to prepare a test piece. Thetensile speed was set to 500 mm/min.

TABLE 1 Example 1 2 3 4 5 6 7 8 Acid-modified SEBS 70 75 80 70 75 80 7575 SPS 30 25 20 30 25 20 25 25 Hydrogenated DCPD 0 0 0 10 10 10 0 0Phenolic antioxidant 1.5 1.5 1.5 1.5 1.5 1.5 0.5 1.5 Phosphorous acidester- 2.0 2.0 2.0 2.0 2.0 2.0 2.0 1.0 based antioxidant MeasuredSealing 200 or 200 or 200 or 200 or 200 or 200 or 200 or 200 or valueproperty (kPa) more more more more more more more more EvaluationSealing property A A A A A A A A Adhesiveness A A A A A A A A Heatresistance A A A A A A A A

TABLE 2 Example 9 10 11 12 13 14 15 Acid-modified SEBS 75 75 75 75 75 7575 SPS 25 25 25 25 25 25 25 Hydrogenated DCPD 0 5 20 0 0 0 0 Phenolicantioxidant 1.5 1.5 1.5 0.2 1.5 2.0 1.5 Phosphorous acid ester- 3.0 2.02.0 2.0 0.5 2.0 4.0 based antioxidant Measured Sealing 200 or 200 or 200or 200 or 200 or 150 130 value property (kPa) more more more more moreEvaluation Sealing property A A A A A B B Adhesiveness A A A A A B BHeat resistance A A A B B B B

TABLE 3 Comparative Example 1 2 3 4 5 Acid-modified SEBS 90 50 30 90 75SPS 10 50 70 10 25 Hydrogenated DCPD 0 0 0 10 30 Phenolic antioxidant1.5 1.5 1.5 1.5 1.5 Phosphorous acid ester- 2.0 2.0 2.0 2.0 2.0 basedantioxidant Measured Sealing 200 or 30 10 200 or 200 or value property(kPa) more more more Evaluation Sealing property A C C A A AdhesivenessA C C A A Heat resistance C B B C C

TABLE 4 Compar- Compar- Exam- Exam- ative Ex- ative Ex- ple 1 ple 4ample 1 ample 4 Acid-modified SEBS 70 70 90 90 SPS 30 30 10 10Hydrogenated DCPD 0 10 0 10 Phenolic antioxidant 1.5 1.5 1.5 1.5Phosphorous acid 2.0 2.0 2.0 2.0 ester-based antioxidant MeasuredSpecific gravity 0.96 0.97 0.94 0.95 value Hardness 86 85 84 82(immediately) Hardness (after 85 84 82 79 10 seconds) Tensile 13.5 17.315.6 28 strength (MPa) Percentage 400 450 530 600 elongation at break(%)

In the case of the formed article obtained using the thermoplasticelastomer resin composition of the present invention, as shown byExamples 1 to 15 in Tables 1 and 2, good results were obtained in all ofsealing property, adhesiveness and heat resistance, and it is confirmedthat the formed article has sealing property, adhesiveness and heatresistance required particularly when mold-forming it to closely adhereto the terminal fitting or the coat part of the electric wire. On theother hand, in the case of the formed article of Comparative Example, asshown by Comparative Examples 1 to 5 in Table 3, good results were notobtained in at least one of sealing property, adhesiveness and heatresistance, and the formed article does not have sealing property,adhesiveness and heat resistance required particularly when mold-formingit to closely adhere to the terminal fitting or the coat part of theelectric wire.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope of the invention. This applicationis based on Japanese Patent Application (Patent Application No.2009-185657) filed on Aug. 10, 2009, the contents of which areincorporated herein by way of reference.

INDUSTRIAL APPLICABILITY

The thermoplastic elastomer composition of the present invention can beprocessed by mold forming and at the same time, is excellent in thesealing property and recycling property, and therefore, the compositioncan be utilized for a connector member of automobiles, home electricappliance, and the like.

DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 1, 1A Connector 2 Terminalfitting 3 Housing part 4, 4A Water-stopping part 6 Electric wire 6a End21 Electric contact part 22 Electric wire connection part 33, 33AElectric wire lead-out port 52 O-ring (seal member)

The invention claimed is:
 1. A thermoplastic elastomer resin compositioncomprising 100 parts by weight of a base resin containing from 60 to 80wt % of an acid-modified styrene-based elastomer and from 40 to 20 wt %of a syndiotactic polystyrene, from 0 to 20 parts by weight of ahydrogenated dicyclopentadiene, from 0.5 to 1.5 parts by weight of aphenolic antioxidant and from 1.0 to 3.0 parts by weight of aphosphorous acid ester-based antioxidant.
 2. A connector, wherein atleast a part of the members are formed of the thermoplastic elastomerresin composition according to claim
 1. 3. A connector comprising aterminal fitting having an electric contact part put into connection toa terminal fitting of the other-party connector and an electric wireconnection part continuing from the electric contact part and beingconnected to the end of an electric wire, at least a part of theelectric contact part being disposed in a first mold resin, the portionbetween the electric contact part and the first mold resin being sealedwith an annular seal member, the electric wire connection part beingembedded in the first mold resin, and the electric wire and the electricwire lead-out port of the first mold resin being sealed with a secondmold resin, wherein the second mold resin is formed of the thermoplasticelastomer resin composition according to claim
 1. 4. The connector asclaimed in claim 3, wherein said first mold resin is formed of a resincomposition containing at least one resin selected from the groupconsisting of a polystyrene-based resin, a polyamide-based resin, apolyester-based resin, a modified polyphenylene ether and apolyphenylene sulfide.